Hi group, I have a sliding door in my condo and have two issues.
1. There is a low spot in the door frame right in the center.
2. The left wheel when looking out the door, is broken and hangs down as I lift the door up, I tried to loosen the screw that raises the wheel but it came out so not sure what is happening. The door is from 1983, so not sure what brand it is or really what to do.

Some doors have to be as close to full open as you can before you can lift them out. With a hanging wheel it will be a two person job. One to lift the door and one to deal with the wheel with a flat scraper or something. If the droop is still a problem, sometimes depending on the flooring on the inside you can remove the molding below and wedge up the center. You are chancing a break in the fixed window. And welcome.